Pressure sensitive record material



Patented Apr. 25, 195i? UNITED STATES PATENT OFFlE 2 ,505,480 PRESSURE SENSITIVE RECORD MATERIAL Barrett K. diee Dayton, Ollie, assiefiar a; 'Ili Nansen cash Register Company, Dayton, onto" a cipdrati'oriof Maryland N0 Drawin Or inal pp icationfiovember 8; 1347, Serial N0. 784,938. this ap; plication November 10, 1948, Serial No. 59,430

1"2'Clalims.

This invention mates to mprtv ments' in pressure-sensitive record material. This applieat'i'on is a division of the pendingapplication qr Barrett serial No. 784,938, filed November 8; 1947, for Pressure' sen'sitive' record material; Y i

The principal object" of this invention is" to provide a pressure slnsitiv' record material on which a mark of di i f color may be are duced by the" mere app atio'h of localized pl sure and" which is not subject to' the disacl" rages inherent in the pressur' sen'sitive' material disclosed in United States Letters Pitttent No. 2,2995%, patented Oct ber 20; 1942, on the application" fil'ed'by' Bar'r'e'tt K. Green on February 23; 1940. That patentdisclosed' a pressure-sensitive record material including the combination of an insulating medium, a ruptur able solid" material such as'gum" damrnar, Having ii'icludedi therein interspersed droplets of a phirality of liquid reagents} which are chemicall? reactive to produce" a di' iii'ctive'" color in the record material at the ptints or appucatidn of localized ressure thereto, such pressure ruptur mg the ihsulating" mediumj to permit chemical reaction between the two liquid rea'gants'. The two reage' 6s disclosed in this patent areame acid and" ferric ammonium sulphate; eachis solved in glyc'erine; I These reagents are ionize'd by the glycer e; wh constitutes an ionizing medium; and the c' c'nical reaenea proceeds by interchange of inne when the two sense-es are allows to n'i izigcpcn' tne rupture of the in: sul'at diumu The reactiondisclosed inthat pat dppendsupon the preserfceof the re its inionizing medium; Hn'we'ver; any avai aole ionizing medium is hygroscopic, with the result that the recordmatefialmade in accordance with this patent is sensitive to an excess of moistiire, and conditions of high humidity maycause" the insulating: medium to'ceas'e to be eiiect'ive, with the result that the chemical reaction takes'place without any application oi localized pressure, and the record-materialis stained and discolored, so that it ceases to-be useful;

As" stated above, theprincipal object" or the present invention is to provide a pre'ssure-'sehsi'- tive recordmaterialthatis not subject to-thede= feats and disadvamtages-of that 'discl'o'sed in Pat ent No: 2,299,693; asindicated above.

Another object of the'present invention is to provide arecordmaterial uponwhich amarkof distinctive color may be produced; at the points or application of localized pressure thereto;- by

such mere application of localized pressure; and r 2 which win net ecome discolored or ames due to the efiect'of light, atmospheric conditions, or aging. I A

In short, it is the object of this invention to provide a pressure-sensitive record' material in which the mark of distinctive color will be pm: duced only at the points of application of localiz'ed pressure, and at no other points, and under no other conditions; i H I Another objector this invention is to provide a pressure-sensitive record material in which themarkof distinctive color is produced by the chemical reaction of color-forming reactants, in the absence 'of' any liquid ionizing medium therefor.

A further object of this" intention is to provide a pressure-sensitive record material in which a mark of distinctive" color is" produced by a reaction between solid particles of colorforming reactants.

Further objects; and objects relating to deftails and economies" of production, will definitely appear from the detaileddescription' to follow. The objects of thisinvention have been attained by the several embodiments therof described in detail" in the following specification. This inventic'n isclearly defined and pointed out in the appended'clai'ma i I In general, the present invention contemplates a pressure-sensitive record material comprising, in combination, afplurality of adsorp tion color-forming reactants, such reactants beso selected that they react, in the absence of a liquid ionizing medium for the reactants, to

form a distinctive color when brought into ad'- sorption contact with each other, and a solid insulating medium insulating said reactants from color-forming reaction contact with each other. Upon application of localized pressure tcthe record material, as by drawing a stylus across it, the insulating medium is ruptured at the points of application of said loc'alied pres sure, and such rupture permits color-forming reaction contact between the reactants at such points, in the absence of any liquid ionizing medium for said reactants. The result is that amark of distinctive color is produced by the mere application of localized pressure.

The color-forming reaction employed is of the, so-called adsorption typein which an inorganic compound causes a color change in an organic compound upon adsorption contact therewith;

Of the rea'e ant maerins employed the ganic material is an electron donor aromatic compound having a double bond system which is convertible to a more highly polarized congugated form upon taking part in an electron acceptor-donor solid surface chemical reaction, giving it a distinctive color, and the inorganic material is a material which is an acid relative to the organic material so as to be an electron acceptor when in adsorption contact therewith. Both materials are in fine particle form in order to furnish a large reactant surface area per unit area of the record material which enhances the depth of color per unit area of the record material.

In the preferred form of this invention, both of the color-forming reactants, as well as the insulating medium, are in the solid state, and the color-forming reaction takes place upon mere contact of solid particles of the reactants. A pressure-sensitive record material may be provided in which the solid particles of a plurality of color-forming reactants are dispersed in a solid insulating medium, which insulates the particles from color-forming reaction contact with each other. The rupture of this solid insulating medium by the application of localized pressure permits the solid particles of colorforming reactants to react with each other, at the points of application of such pressure, to produce the mark of distinctive color. According to one form of this invention, solid particles of one of the color-forming reactants are carried by and dispersed in a solid insulating medium, to which a coating of solid particles of another color-forming reactant is applied. In this case, the application of localized pressure ruptures the solid insulating medium at the points of application of such pressure and brings about colorforming reaction contact between the solid particles of color-forming reactants at such points, thus producing the mark of distinctive color. Preferably, this pressure-sensitive record material includes a base web, such as a fibrous web of paper or the like, to which the coating of solid insulating medium and the color-forming reactants is applied.

Since it is difiicult to show precisely the spatial relationship between the solid particles of color-forming reactants, the solid insulating medium, and the base web, it is preferred not to attempt to illustrate any embodiment of this invention by drawings.

In the following examples, there will be described embodiments of this invention, by means of which the objects of the invention have been successfully attained.

A pressure-sensitive record material constituting an embodiment of this invention consists of a web of paper having applied thereto a coating including casein as the solid insulating medium and solid particles of two color-forming reactants; namely, kaolin and the compound l'(p 'dimethylaminophenylazo) benzanilide, having the structural formula This record material is normally light yellow in color, but the application of localized pressure thereto produces a dark brown mark thereon at the points of application of such pressure. The solid insulating medium, casein, insulates the solid particles of kaolin and the solid particles of the compound 4-(p-dimethylaminophenylazo) benzanilide from color-forming reaction contact with each other, but said insulating medium is ruptured at the points of application of such pressure, permitting color-forming reac-- tion Contact between the solid particles of the reactants and thus producing the distinctive mark.

The record material described above has beer. made successfully by coating a web of paper with a casein solution having solid particles of kaolin dispersed therein, the ratio or kaolin to casein being about ten to one. After drying this coating on the paper, the coated side or the paper was treated with a 0.5% by weight solution in toluene of the compound 4-(p-dimethylaminophenylazo) benzanilide. After removing the excess solution from the treated paper, the latter was dried to evaporate the solvent.

When these ingredients are applied to the paper as a coating thereon, such coating weighs about .0023 pound per square foot of surface and may have a thickness of the order of from .0005 to .001 inch. The thickness of the coating varies, of course, with the treatment to which the record material is sub ected in finishing. The solid particles of kaolin in this record material may be of about the order of ten microns in diameter, although considerable variation in particle size is possible without any ill effects. Particle size of the benzanilide compound is largely determined by the metiluu. of application of that ingredient. The particles of these reactants may be as large as ten microns in diameter and frequently are much smaller.

Organic film-forming hydrophilic colloid substances as gelatin, methyl cellulose, starch, poly vinyl alcohol, and animal glue are representative materials that may be substituted for casein as the solid insulating medium. Any of the following inorganic materials may be substituted for kaolin as one of the color-forming reactants: attapulgite (Attapulgus clay), pyrophyllite, talc, bentonite, halloysite, calcium sulphate, calcium citrate, magnesium trisilicate, zinc sulphide, zirconium dioxide, calcium phosphate, barium sulphate, and calcium fluoride. When any of these materials are substituted for the kaolin in this combination, the resulting record material will be light yellow in color, and a dark brown mark will appear thereon as the result of the application of localized pressure.

The methods and processes of making pressure-sensitive record material disclosed herein are not claimed in this application but are disclosed and claimed in the pending application of Barrett K. Green, Serial No. 784,939, filed November 8, 1947, for Process for making pressuresensitive record material, and in the division thereof, Serial No. 63,219, filed December 2, 1948.

It is understood that the pressure-sensitive record material described herein is susceptible of considerable variation without departing from the spirit of the invention.

What is claimed is:

1. Pressure-sensitive record material including the combination of a supporting member, a plurality of adsorption color-forming reactants in the solid state, so selected as to react in the absence of a liquid ionizing medium for the reactants to form a distinctive color when brought into contact with each other, at least one of the reactants being an inorganic compound and at least another one of the reactants being an organic compound, disposed in proximity to each other, and a solid insulating medium, derived from an organic film-forming hydrophilic colloird substance, insulating said reactants from collor-forming reaction contact with each other, thf application of localized pressure to the record jiaterial rupturing said insulating medium at he points of application of such pressure to permit color-forming reaction contact between the reactants at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of the color-forming reactants being the organic compound 4-(pdimethylaminophenylazo) benzanilide, having the structure and the inorganic reactant being in fine particle form to provide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound, the organic and inorganic reactants being adsorbable one upon the other.

2. The record material of claim 1 in which the inorganic color-forming reactant is kaolin.

3. The record material of claim 2 in which the solid insulatin medium is casein.

4. Pressure-sensitive record material including the combination of a supporting member, solid particles of a plurality of adsorption colorforming reactants disposed in contiguity to each other, and a solid insulating medium, derived from an organic film-forming hydrophilic colloid substance insulating said solid reactant particles from color-forming reaction contact with each other, at least one of the reactants being an inorganic compound and at least another one of the reactants being an organic compound adsorbable one upon the other, said reactants being so selected as to react to form a distinctive color when particles of each are brought into adsorption contact, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contact of the solid reactant particles at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of the color-forming reactants being the organic compound 4' (p dimethylaminophenylazo) benzanilide, having the structure solid insulating medium, derived from an organic film-forming hydrophilic colloid substance, solid particles of a first color-forming reactant dispersed therein and solid particles of a second color-forming reactant deposited thereon, said solid insulating medium insulating said solid reactant particles from color-forming reaction contact with each other, one of said reactants being an inorganic compound and the other of 75 said reactants being an organic compound one adsorbable upon the other, said reactants being so selected as to react, in the solid state, to form a distinctive color when brought into adsorption contact with each other, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contacts of the solid reactant particles at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, the second color-forming reactant being the organic compound 4-(p-dimethylaminophenylazo) benzanilide, having the structure and the inorganic reactant being in fine particle form to provide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound.

8. The record material of claim 7 in which the first color-forming reactant is kaolin.

9. The record material of claim 8 in which the solid insulating medium is casein.

10. Pressure-sensitive record material including the combination of a web, and a coating on the web including a solid insulating medium derived from an organic film-forming hydrophilic colloid substance, and solid particles of a plurality of adsorption color-forming reactants interspersed in said solid medium and insulated thereby from color-forming reaction contact with each other, at least one of said reactants being an inorganic compound and at least one other of said reactants being an organic compound one adsorbable upon the other, said reactants having the property of reacting to form a distinctive color when particles of each are brought into contact, the application of localized pressure to the record material rupturing said insulating medium at the points of application of pressure to permit color-forming reaction contact of the solid reactant particles at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of the color-forming reactants being the organic compound 4-(p-dimethylaminoazo) benzanilide, having the structure BARRETT K. GREEN.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Country Date Great Britain Jan. 4, 1943 Number Certificate of Correction Patent No. 2,505,480 o April 25, 1950 BARRETT K. GREEN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, lines 56 and 51, for 4.'-(p-dimethylaminoazo) read 4-(p-d1 methyla-minophem lazo) and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 8th day of August, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommz'ssioner of Patents. 

1. PRESSURE-SENSITIVE RECORD MATERIAL INCLUDING THE COMBINATION OF A SUPPORTING MEMBER, A PLURALITY OF ADSORPTION COLOR-FORMING REACTANTS IN THE SOLID STATE, SO SELECTED AS TO REACT IN THE ABSENCE OF A LIQUID IONIZING MEDIUM FOR THE REACTANTS TO FORM A DISTINCTIVE COLOR WHEN BROUGHT INTO CONTACT WITH EACH OTHER, AT LEAST ONE OF THE REACTANTS BEING AN INORGANIC COMPOUND AND AT LEAST ANOTHER ONE OF THE REACTANTS BEING AN ORGANIC COMPOUND, DISPOSED IN PROXIMITY TO EACH OTHER, AND A SOLID INSULATING MEDIUM, DERIVED FROM AN ORGANIC FILM-FORMING HYDROPHILIC COLLOID SUBSTANCE, INSULTING SAID REACTANTS FROM COLOR-FORMING REACTION CONTACT WITH EACH OTHER, THE APPLICATION OF LOCALIZED PRESSURE TO THE RECORD MATERIAL RUPTURING SAID INSULATING MEDIUM AT THE POINTS OF APPLICATION OF SUCH PRESSURE TO PERMIT COLOR-FORMING REACTION CONTACT BETWEEN THE REACTANTS AT SUCH POINTS, WHEREBY A MARK OF DISTINCTIVE COLOR IS PRODUCED BY MERE APPLICATION OF LOCALIZED PRESSURE, ONE OF THE COLOR-FORMING REACTANTS BEING THE ORGANIC COMPOUND 4''-(PDIMETHYLAMINOPHENYLAZO) BENZANILIDE, HAVING THE STRUCTURE. 